Medical
One hundred to two hundred thousand tissue transplants are annually performed in the United States. Thus, it is in the realm of preparing these samples that the present invention will find tremendous medical applications. The single most variable factor with respect to allographic transplantation is the preparation of such bone and tissue segments. Procedure and protocol of the sum 400 tissue banks in North America is quite varied and has resulted in a void of technology with developed process at a cost effective level. There is no known industry standard specifying levels of cleanliness for cleaning and preparing bone segments. The problems associated with this lack of standards interpret to poor process control, inadequate removal of tissue from the parent surface and to a large extent lack of sterility during the cleaning process.
The upper portion of FIG. 12 shows the known process, generally designated 400, relating to allotropic tissues, as beginning by removal of a segment from a donor 401, generally a cadaveric donor within 24 hours after cessation of life. Upon removal of large segments, i.e. the pelvis, the long bones of the legs, and intact joints, then the outer fleshy components and connective tissue, ligamentary tissues, are removed from the bone, via osteotomies 402 that are mechanical hand held instruments adapted for cleaning and preparing the bone tissues and for use in close contact with the bone segment surface for removal of fleshy connective tissues from the bone. The removal of the large segments may or not be done in a sterile environment, i.e. a hospital morgue, a side room at less than operating room sterility. The segments are then subjected to a low pressure, often nonsterile fluid 402 such as tap water at 35 to 40 p.s.i. The most modern method of cleaning bone segments still use the osteotomies but may use a low delivery non-sterile fluid but use clean room environment to do the cleaning of the bone segment. The osteotome cleaned bone segments are not considered sterile and are thus further processed with a secondary sterilant, generally using liquid and gaseous ethylene oxide 403 or gamma irradiation 404. Alternatively, the segment may be preserved using lyophilization techniques 405. The lyophilization does not sterilize but rather removes water to prevent further growth of any virus. The gamma irradiation 404 and ethylene oxide 403 processes, while providing a sterile segment, neither will get the segment any cleaner. Both processes are known to have deleterious effects at the oncogenic and mutagenic potential levels. The segments sterilized using etheyene oxide (eto) may be stored, in a suitable storage facility 406 for six months then the segments must be reintroduced to the eto sterilization process. The resterilization may only be done a maximum of three times, then the segment must be discarded. Obviously, a costly situation exists in addition to the mutagenic and oncogenic risks.